What would cause busted blood vessels in my wrists?

Trauma is the most typical cause. As we age the collagen in our vessels get weaker and the vessels are prone to rupture with little trauma. Baring this it is possible to have vasculitis causing this. If you are concerned you should see your doctor to be formally evaluated for this.

The most common cause of a busted blood vessel is traumatic injury. Any pressure or force exerted on your wrist could cause the vein inside to rupture causing discoloration of the surrounding skin. The amount of force needed to burst a blood vessel varies, so for some people this is a more common occurrence.

An injury or a strain could damage the blood vessels in your wrists, causing them to burst. If you're taking any blood thinners it could also exacerbate the condition. It should heal with rest and icing the area.